FAQ-What Is the Cause of TE Tunnel Failing to Be Up and How to Check it

Publication Date: 2012-07-27Views: 125Downloads: 0

Issue Description

Q: What is the cause of TE Tunnel failing to go up? How to check it?

Alarm Information

Null

Handling Process

A: TE tunnel sometimes cannot go up, and you can take the following steps:1. Run display current-configuration configuration mpls command to check if all the routers have enabled mpls/mpls te/mpls rsvp-te/mpls te cspf, as follows: [Quidway]disp cur c mplsmpls lsr-id 23.23.23.23 mpls mpls te mpls rsvp-te mpls te cspf2 If OSPF is used as IGP, check if OSPF TE extention (OSPF TE extention has two commands: opaque-capability enable and mpls-te enable) has been enabled also; if ISIS is used as IGP, check if ISIS TE extention (ISIS TE extention has two commands traffic-eng and cost wide)3. Check if all the links have enabled mpls te/mpls rsvp-te/mpls max-reservable-bandwidth (if necessary to reserve the bandwidth, max-reservable-bandwidth is required), as follows: [Quidway]disp cur int gi2/1/0interface GigabitEthernet2/1/0 undo shutdown ip address 2.23.26.1 255.255.255.0 mpls mpls te mpls te max-link-bandwidth 10000000 bc1 5000000 mpls te max-reservable-bandwidth 1000000 bc1 500000 mpls rsvp-te4. Check if the destination address of tunnel is reachable. Ping the destination address configured for the tunnel to check the connectivity. 5. After configuring the attributes of tunnel in tunnel interface view, run mpls te commit to submit it and then it can take effect. In addition, the tunnel interface cannot be shutdown.6. If explicit path is configured, check if links that the path passes are in correct state, and if the reserved bandwidth suffices. 7. The destination of tunnel would better be the loopback interface of router if the loopback address is also mpls lsr-id; otherwise the tunnel cannot go up. For a single loopback interface, it cannot enable mpls te, and it has to use mpls lsr-id as compensation. So if the destination is the loopback address of router, check if the address is also the mpls lsr-id.8. If the problem persists, turn on the debugging switch to check it, with commands as follows: <Quidway>debugging mpls management interface<Quidway>debugging mpls management all<Quidway>debugging mpls te management all<Quidway>terminal debugging% Current terminal debugging is on<Quidway>terminal monitor% Current terminal monitor is on Check the printed debugging information. If CSPF calculation fails as follows: Cspf failed to Calculate Path for Tunnel : Tunnel6/0/0It is possible that there is no proper path to the destination. Check if TEDB database has enough resources to perform CSPF calculation. If it prompts resource application failure, check if the path bandwidth is problematic.9. If the steps above cannot help locate the problem, consult the relevant engineers about the printed debugging information.